package com.zhouke.certificate.config.interceptor;

import cn.hutool.core.util.StrUtil;
import com.auth0.jwt.JWT;
import com.auth0.jwt.JWTVerifier;
import com.auth0.jwt.algorithms.Algorithm;
import com.auth0.jwt.exceptions.JWTDecodeException;
import com.auth0.jwt.exceptions.JWTVerificationException;
import com.zhouke.certificate.common.Constants;
import com.zhouke.certificate.config.AuthAccess;
import com.zhouke.certificate.entity.User;
import com.zhouke.certificate.exception.ServiceException;
import com.zhouke.certificate.service.IUserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.method.HandlerMethod;
import org.springframework.web.servlet.HandlerInterceptor;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

/**
 * token拦截器
 * http请求 头部拦截器 获取token判断是否需要登录
 */
public class JwtInterceptor implements HandlerInterceptor {
    @Autowired
    private IUserService userService;
    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler){
        String token = request.getHeader("token");
        //如果不是映射到方法直接通过 （如果是预请求则不做处理）
        if(!(handler instanceof HandlerMethod)){
            return true;
        }else{//是controller中的方法
            HandlerMethod h=(HandlerMethod) handler;
            AuthAccess authAccess=h.getMethodAnnotation(AuthAccess.class);
            if(authAccess!=null){
                return true;
            }
        }
        //执行认证
        if(StrUtil.isBlank(token)){
            throw new ServiceException(Constants.CODE_401,"无token，请重新登录");
        }
        //获取 token 中的 user id
        String userId;
        try{
            userId= JWT.decode(token).getAudience().get(0);
        }catch (JWTDecodeException j){
            throw new ServiceException(Constants.CODE_401,"token验证失败");
        }
        //根据token中的userid查询数据库
        User user= userService.getById(userId);
        if(user==null){
            throw new ServiceException(Constants.CODE_401,"用户不存在，请重新登录");
        }
        //用户密码加密 验证token 密码
        JWTVerifier jwtVerifier=JWT.require(Algorithm.HMAC256(user.getPassword())).build();
        try{
            jwtVerifier.verify(token); //验证token
        }catch (JWTVerificationException j){
            throw new ServiceException(Constants.CODE_401,"token密码验证失败，请重新登录");
        }

        return true;
    }
}
